print all items saved in a core data string1 - swift

Question

I want my swift code to print out the strings attributes. Right now when calling the function I am getting a runtime error at context. I just want to print out all of each string entry. I have added the function in question below.
Thread 1: Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value
let appDelegate = UIApplication.shared.delegate as! AppDelegate //Singlton instance
var context:NSManagedObjectContext!
#objc func pressRight(){
let fetchRequest = NSFetchRequest<Place>(entityName: "Name")
do {
let result = try context.fetch(fetchRequest)
let nameArray = result.map{$0.name}
print(nameArray)
} catch {
print("Could not fetch \(error) ")
}
}
pic

Answer 1

select manual in code gen
then create custom class of place add to your project
You are using the wrong entity name "Name" instead of "Place"
import Foundation
import CoreData
class CoreDataManager {
static let shared = CoreDataManager()
private init() {}
lazy var coreDataStack = CoreDataStack(modelName: "Place")
func allNames() -> [String]? {
let request: NSFetchRequest<Place> = Place.fetchRequest()
do {
// Peform Fetch Request
let places = try coreDataStack.managedContext.fetch(request)
return places.map({$0.name})
} catch {
print("Unable to Fetch Workouts, (\(error))")
}
return nil
}
func allPlaces() -> [Place]? {
let request: NSFetchRequest<Place> = Place.fetchRequest()
do {
// Peform Fetch Request
let places = try coreDataStack.managedContext.fetch(request)
return places
} catch {
print("Unable to Fetch Workouts, (\(error))")
}
return nil
}
}
if you still getting error then before this initialize your context
managedObjectContext/context you force unwrapping it
add this stack class
import Foundation
import CoreData
class CoreDataStack {
private let modelName: String
lazy var managedContext: NSManagedObjectContext = {
return self.storeContainer.viewContext
}()
init(modelName: String) {
self.modelName = modelName
}
private lazy var storeContainer: NSPersistentContainer = {
let container = NSPersistentContainer(name: self.modelName)
container.loadPersistentStores { storeDescription, error in
if let error = error as NSError? {
print("Unresolved error \(error), \(error.userInfo)")
}
}
return container
}()
func saveContext() {
guard managedContext.hasChanges else {return}
do{
try managedContext.save()
} catch let error as NSError {
print("Unresolved error \(error), \(error.userInfo)")
}
}
func updateContext() {
do {
try managedContext.save()
} catch let error as NSError {
print("Unresolved error \(error), \(error.userInfo)")
}
}
func clearChange() {
managedContext.rollback()
}
}
then how to use it
in your view controller viewDidLoad() function or any other button tap action you can get your place names like this
override func viewDidLoad() {
super.viewDidLoad()
// here you get all names
let names = CoreDataManager.shared.allNames()
print(names)
let places = CoreDataManager.shared.allPlaces()
print(places)
let namesAgain = places.map({$0.name})
print(namesAgain)
}